// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_ITOA_
#define RAPIDJSON_ITOA_

#include "../rapidjson.h"

RAPIDJSON_NAMESPACE_BEGIN
namespace internal
{

    inline const char* GetDigitsLut()
    {
        static const char cDigitsLut[200] = {
            '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0', '7', '0',
            '8', '0', '9', '1', '0', '1', '1', '1', '2', '1', '3', '1', '4', '1', '5', '1', '6',
            '1', '7', '1', '8', '1', '9', '2', '0', '2', '1', '2', '2', '2', '3', '2', '4', '2',
            '5', '2', '6', '2', '7', '2', '8', '2', '9', '3', '0', '3', '1', '3', '2', '3', '3',
            '3', '4', '3', '5', '3', '6', '3', '7', '3', '8', '3', '9', '4', '0', '4', '1', '4',
            '2', '4', '3', '4', '4', '4', '5', '4', '6', '4', '7', '4', '8', '4', '9', '5', '0',
            '5', '1', '5', '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5',
            '9', '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6', '7',
            '6', '8', '6', '9', '7', '0', '7', '1', '7', '2', '7', '3', '7', '4', '7', '5', '7',
            '6', '7', '7', '7', '8', '7', '9', '8', '0', '8', '1', '8', '2', '8', '3', '8', '4',
            '8', '5', '8', '6', '8', '7', '8', '8', '8', '9', '9', '0', '9', '1', '9', '2', '9',
            '3', '9', '4', '9', '5', '9', '6', '9', '7', '9', '8', '9', '9'};
        return cDigitsLut;
    }

    inline char* u32toa(uint32_t value, char* buffer)
    {
        RAPIDJSON_ASSERT(buffer != 0);

        const char* cDigitsLut = GetDigitsLut();

        if (value < 10000)
        {
            const uint32_t d1 = (value / 100) << 1;
            const uint32_t d2 = (value % 100) << 1;

            if (value >= 1000)
                *buffer++ = cDigitsLut[d1];
            if (value >= 100)
                *buffer++ = cDigitsLut[d1 + 1];
            if (value >= 10)
                *buffer++ = cDigitsLut[d2];
            *buffer++ = cDigitsLut[d2 + 1];
        }
        else if (value < 100000000)
        {
            // value = bbbbcccc
            const uint32_t b = value / 10000;
            const uint32_t c = value % 10000;

            const uint32_t d1 = (b / 100) << 1;
            const uint32_t d2 = (b % 100) << 1;

            const uint32_t d3 = (c / 100) << 1;
            const uint32_t d4 = (c % 100) << 1;

            if (value >= 10000000)
                *buffer++ = cDigitsLut[d1];
            if (value >= 1000000)
                *buffer++ = cDigitsLut[d1 + 1];
            if (value >= 100000)
                *buffer++ = cDigitsLut[d2];
            *buffer++ = cDigitsLut[d2 + 1];

            *buffer++ = cDigitsLut[d3];
            *buffer++ = cDigitsLut[d3 + 1];
            *buffer++ = cDigitsLut[d4];
            *buffer++ = cDigitsLut[d4 + 1];
        }
        else
        {
            // value = aabbbbcccc in decimal

            const uint32_t a = value / 100000000; // 1 to 42
            value %= 100000000;

            if (a >= 10)
            {
                const unsigned i = a << 1;
                *buffer++        = cDigitsLut[i];
                *buffer++        = cDigitsLut[i + 1];
            }
            else
                *buffer++ = static_cast<char>('0' + static_cast<char>(a));

            const uint32_t b = value / 10000; // 0 to 9999
            const uint32_t c = value % 10000; // 0 to 9999

            const uint32_t d1 = (b / 100) << 1;
            const uint32_t d2 = (b % 100) << 1;

            const uint32_t d3 = (c / 100) << 1;
            const uint32_t d4 = (c % 100) << 1;

            *buffer++ = cDigitsLut[d1];
            *buffer++ = cDigitsLut[d1 + 1];
            *buffer++ = cDigitsLut[d2];
            *buffer++ = cDigitsLut[d2 + 1];
            *buffer++ = cDigitsLut[d3];
            *buffer++ = cDigitsLut[d3 + 1];
            *buffer++ = cDigitsLut[d4];
            *buffer++ = cDigitsLut[d4 + 1];
        }
        return buffer;
    }

    inline char* i32toa(int32_t value, char* buffer)
    {
        RAPIDJSON_ASSERT(buffer != 0);
        uint32_t u = static_cast<uint32_t>(value);
        if (value < 0)
        {
            *buffer++ = '-';
            u         = ~u + 1;
        }

        return u32toa(u, buffer);
    }

    inline char* u64toa(uint64_t value, char* buffer)
    {
        RAPIDJSON_ASSERT(buffer != 0);
        const char*    cDigitsLut = GetDigitsLut();
        const uint64_t kTen8      = 100000000;
        const uint64_t kTen9      = kTen8 * 10;
        const uint64_t kTen10     = kTen8 * 100;
        const uint64_t kTen11     = kTen8 * 1000;
        const uint64_t kTen12     = kTen8 * 10000;
        const uint64_t kTen13     = kTen8 * 100000;
        const uint64_t kTen14     = kTen8 * 1000000;
        const uint64_t kTen15     = kTen8 * 10000000;
        const uint64_t kTen16     = kTen8 * kTen8;

        if (value < kTen8)
        {
            uint32_t v = static_cast<uint32_t>(value);
            if (v < 10000)
            {
                const uint32_t d1 = (v / 100) << 1;
                const uint32_t d2 = (v % 100) << 1;

                if (v >= 1000)
                    *buffer++ = cDigitsLut[d1];
                if (v >= 100)
                    *buffer++ = cDigitsLut[d1 + 1];
                if (v >= 10)
                    *buffer++ = cDigitsLut[d2];
                *buffer++ = cDigitsLut[d2 + 1];
            }
            else
            {
                // value = bbbbcccc
                const uint32_t b = v / 10000;
                const uint32_t c = v % 10000;

                const uint32_t d1 = (b / 100) << 1;
                const uint32_t d2 = (b % 100) << 1;

                const uint32_t d3 = (c / 100) << 1;
                const uint32_t d4 = (c % 100) << 1;

                if (value >= 10000000)
                    *buffer++ = cDigitsLut[d1];
                if (value >= 1000000)
                    *buffer++ = cDigitsLut[d1 + 1];
                if (value >= 100000)
                    *buffer++ = cDigitsLut[d2];
                *buffer++ = cDigitsLut[d2 + 1];

                *buffer++ = cDigitsLut[d3];
                *buffer++ = cDigitsLut[d3 + 1];
                *buffer++ = cDigitsLut[d4];
                *buffer++ = cDigitsLut[d4 + 1];
            }
        }
        else if (value < kTen16)
        {
            const uint32_t v0 = static_cast<uint32_t>(value / kTen8);
            const uint32_t v1 = static_cast<uint32_t>(value % kTen8);

            const uint32_t b0 = v0 / 10000;
            const uint32_t c0 = v0 % 10000;

            const uint32_t d1 = (b0 / 100) << 1;
            const uint32_t d2 = (b0 % 100) << 1;

            const uint32_t d3 = (c0 / 100) << 1;
            const uint32_t d4 = (c0 % 100) << 1;

            const uint32_t b1 = v1 / 10000;
            const uint32_t c1 = v1 % 10000;

            const uint32_t d5 = (b1 / 100) << 1;
            const uint32_t d6 = (b1 % 100) << 1;

            const uint32_t d7 = (c1 / 100) << 1;
            const uint32_t d8 = (c1 % 100) << 1;

            if (value >= kTen15)
                *buffer++ = cDigitsLut[d1];
            if (value >= kTen14)
                *buffer++ = cDigitsLut[d1 + 1];
            if (value >= kTen13)
                *buffer++ = cDigitsLut[d2];
            if (value >= kTen12)
                *buffer++ = cDigitsLut[d2 + 1];
            if (value >= kTen11)
                *buffer++ = cDigitsLut[d3];
            if (value >= kTen10)
                *buffer++ = cDigitsLut[d3 + 1];
            if (value >= kTen9)
                *buffer++ = cDigitsLut[d4];

            *buffer++ = cDigitsLut[d4 + 1];
            *buffer++ = cDigitsLut[d5];
            *buffer++ = cDigitsLut[d5 + 1];
            *buffer++ = cDigitsLut[d6];
            *buffer++ = cDigitsLut[d6 + 1];
            *buffer++ = cDigitsLut[d7];
            *buffer++ = cDigitsLut[d7 + 1];
            *buffer++ = cDigitsLut[d8];
            *buffer++ = cDigitsLut[d8 + 1];
        }
        else
        {
            const uint32_t a = static_cast<uint32_t>(value / kTen16); // 1 to 1844
            value %= kTen16;

            if (a < 10)
                *buffer++ = static_cast<char>('0' + static_cast<char>(a));
            else if (a < 100)
            {
                const uint32_t i = a << 1;
                *buffer++        = cDigitsLut[i];
                *buffer++        = cDigitsLut[i + 1];
            }
            else if (a < 1000)
            {
                *buffer++ = static_cast<char>('0' + static_cast<char>(a / 100));

                const uint32_t i = (a % 100) << 1;
                *buffer++        = cDigitsLut[i];
                *buffer++        = cDigitsLut[i + 1];
            }
            else
            {
                const uint32_t i = (a / 100) << 1;
                const uint32_t j = (a % 100) << 1;
                *buffer++        = cDigitsLut[i];
                *buffer++        = cDigitsLut[i + 1];
                *buffer++        = cDigitsLut[j];
                *buffer++        = cDigitsLut[j + 1];
            }

            const uint32_t v0 = static_cast<uint32_t>(value / kTen8);
            const uint32_t v1 = static_cast<uint32_t>(value % kTen8);

            const uint32_t b0 = v0 / 10000;
            const uint32_t c0 = v0 % 10000;

            const uint32_t d1 = (b0 / 100) << 1;
            const uint32_t d2 = (b0 % 100) << 1;

            const uint32_t d3 = (c0 / 100) << 1;
            const uint32_t d4 = (c0 % 100) << 1;

            const uint32_t b1 = v1 / 10000;
            const uint32_t c1 = v1 % 10000;

            const uint32_t d5 = (b1 / 100) << 1;
            const uint32_t d6 = (b1 % 100) << 1;

            const uint32_t d7 = (c1 / 100) << 1;
            const uint32_t d8 = (c1 % 100) << 1;

            *buffer++ = cDigitsLut[d1];
            *buffer++ = cDigitsLut[d1 + 1];
            *buffer++ = cDigitsLut[d2];
            *buffer++ = cDigitsLut[d2 + 1];
            *buffer++ = cDigitsLut[d3];
            *buffer++ = cDigitsLut[d3 + 1];
            *buffer++ = cDigitsLut[d4];
            *buffer++ = cDigitsLut[d4 + 1];
            *buffer++ = cDigitsLut[d5];
            *buffer++ = cDigitsLut[d5 + 1];
            *buffer++ = cDigitsLut[d6];
            *buffer++ = cDigitsLut[d6 + 1];
            *buffer++ = cDigitsLut[d7];
            *buffer++ = cDigitsLut[d7 + 1];
            *buffer++ = cDigitsLut[d8];
            *buffer++ = cDigitsLut[d8 + 1];
        }

        return buffer;
    }

    inline char* i64toa(int64_t value, char* buffer)
    {
        RAPIDJSON_ASSERT(buffer != 0);
        uint64_t u = static_cast<uint64_t>(value);
        if (value < 0)
        {
            *buffer++ = '-';
            u         = ~u + 1;
        }

        return u64toa(u, buffer);
    }

} // namespace internal
RAPIDJSON_NAMESPACE_END

#endif // RAPIDJSON_ITOA_
